FE interfaces are classified into Layer 2 interfaces and Layer 3 interfaces. You can configure IP addresses for Layer 3 FE interfaces. Some FE interfaces can switch between Layer 2 and Layer 3 modes. For example, Ethernet0/0/0 on AR150&AR200 works in Layer 2 mode by default. Run the undo portswitch command to switch from Layer 2 mode to Layer 3 mode. After an FE interface is switched to Layer 3 mode, you can configure IP addresses for the interface.

The DHCP server can be configured on a Layer 3 interface of the Huawei AR to allocate IP addresses to users connected to the Layer 3 interface. In practice, an interface connected to the intranet is enabled with the DHCP server and allocates intranet IP addresses to intranet users. The interface connected to the public network has NAT enabled to communicate with the public network.